In a SCADA system, data respectively gathered by a plurality of remote stations is supplied to a master station and supervisory control is performed on the basis of this data. Each of the remote stations includes a plurality of status-change detectors and a process which gathers data from the detectors and transmits this data to the master station.
The status-change detector in the remote station has the functions of supervising one or more plant apparatus or products of the plant apparatus and storing the occurrence of status-change and data of the plant apparatus. Further, one of the functions of these SCADA systems is communication with the remote station. Generally, these remote stations have been installed along a line at different times, resulting in that these remote stations are of different manufacturer and different processing capabilities. The different remote stations generally have different communication protocols which are required to communicate with these remote stations. A problem has developed in that these communication protocols require a labor-intensive effort in order to establish these different communication protocols within a single central system. One method of achieving these varying communication protocols is to burn software into ROM, creating circuitry software which includes the communication protocol with a specific remote station. This procedure is required to be repeated for each different kind of remote station located along the line and requiring communication to the central station. Thus, a lengthy process is required in order to achieve a communication link with the remote stations. Furthermore, this procedure does not lend itself well to situations where it is desirous of changing the data format in the remote station generally, in order to receive this new data format, it is necessary to again execute the above described procedure.